This project will examine the effects of volatile anesthetics on native sarcolemmal and mitochondrial KATP channels in guinea pig cardiac ventricular cells, and cloned KATP channels expressed in the HEK293 cell line and subjected to different ischemic conditions. Several configurations of the patch-clamp methodology will be used including whole-cell and single channel techniques. The planned experiments will systematically investigate mechanisms by which KATP modulators affect the sensitivity of the channel in the presence of anesthetics. In addition, they will determine the effect of anesthetics on KATP channels in cardiac ventricular cells exposed to ischemic conditions, and characterize how anesthetics alter the effects of KATP channel modulators on channel activity. The effect of anesthetics on the mitochondrial redox potential will also be examined in myocytes exposed to simulated ischemia. Specific Aims are 1) To determine the effects of volatile anesthetics on the sarcolemmal KATP channels in guinea pig myocytes that were subjected to simulated ischemic conditions and characterize how anesthetics alter the effects of KATP channel modulators. The hypothesis tested is that sarcolemmal KATP channels in cardiac myocytes exposed to ischemia and/or volatile anesthetics are more sensitive to KATP channel agonists, adenosine and nitric oxide as compared to KATP channels from nonischemic myocytes. 2) To characterize how inhalational anesthetics alter the sensitivity of mitochondrial KATP channels that were subjected to simulated ischemic conditions and determine how anesthetics and simulated ischemia induce PKC isoform translocation. The hypothesis tested is that VA activate mitochondrial KATP channels via direct and indirect mechanisms, and that VA and simulated ischemia exhibit similar PKC isoform translocation. VA - induced cardioprotection is due to the opening of the mitochondrial KATP channel. 3) To characterize the effect of VA on cloned KATP channels expressed in HEK293 cells. The hypothesis tested is that the effect of VA on expressed KATP channels is attenuated compared to their effect on native KATP channels.